style: gofmt normalization — no logic changes

gofmt -w across the controller tree (46 files) so gofmt -l is empty — disarms the
formatting landmine where a targeted edit + accidental gofmt -w swept ~46 unrelated
files. Pure formatting: whitespace + gofmt's optional-semicolon removal in reflowed
inline closures. One doc comment reworded ('' -> 'the empty string') to avoid gofmt's
Go-1.19 doc-comment typographic substitition ('' -> curly quote) muddying its meaning.
No build/vet/test behavior change.

controller/internal/setup/setup.go

@@ -43,8 +43,8 @@ type SetupState struct {
 
 // SelectedBackup tracks which backup the user chose.
 type SelectedBackup struct {
-	Source     string `json:"source"`      // "local" or "hub"
-	DrivePath  string `json:"drive_path"`  // for local
+	Source     string `json:"source"`     // "local" or "hub"
+	DrivePath  string `json:"drive_path"` // for local
 	CustomerID string `json:"customer_id"`
 	Timestamp  string `json:"timestamp"`
 }